The Core section details facets of operation common to all of the research projects comprising the program project, namely the administration, personnel, clinical and laboratory environments, patient screening methods, and radiological procedures. Included in the administration and personnel sections are the manager of the program project, the patient coordinator, the personnel responsible for patient examinations and neuropsychological testing, and the developer of the image processing system. Detailed descriptions of the facilities available for patient recruitment and for physiologic and behavioral testing are contained in the clinical and environmental sections. Moreover, a comprehensive outline of the procedures used in the screening of patients with focal neurological lesions is provided in the clinical section. Finally, the procedures used in the reconstruction of lesions seen on computed tomography (CT) and magnetic resonance imaging (MRI) are described, as are the rationale and protocol for the use of a three- dimensional MRI technique.